<!DOCTYPE html>
<html>
<head>
<style type="text/css">

#c3, #c4 {
  display: none;
}

input:checked + label {
  background-color: yellow;
}

</style>

<script type="text/javascript">

function toggleAllCheckboxes()
{
  for (var i = 1; i <= 4; ++i) {
    var cb = document.getElementById('c'+i);
    cb.checked = !cb.checked;
  }
}

</script>
</head>

<body onload="toggleAllCheckboxes();">

<div><input type="checkbox" name="test" id="c1"><label for="c1">check #c1</label></div>
<div><input type="checkbox" name="test" id="c2" checked><label for="c2">check #c2</label></div>
<div><input type="checkbox" name="test" id="c3"><label for="c3">check #c3</label></div>
<div><input type="checkbox" name="test" id="c4" checked><label for="c4">check #c4</label></div>

</body>
</html>
